For sure, you will notice a big difference from 8.8m to 10m. I'm similar weight to you (105kg) on an 85cm XL slalom and feel a big benefit when I switch from 9m to 10m (and bigger fin). Pumping is easier, faster exit out of jibs, better acceleration, better angles up/down wind and generally feeling more powered up. In fact, 8.8m is about as small as you should go on an XL slalom, is yours a JP Slalom 82?